The advent of electric lighting introduced various lighted display means for providing messages capable of being illuminated during non-daylight hours. One early method of providing illuminated signage was through the use of a high voltage discharge through an inert gas, with neon being particularly preferable, as is well-known in the art. Another early method involved the use of a plurality of incandescent lamps arranged in a selected pattern, which were intermittently flashed on and off so as to produce a visual effect resembling the movement of words from one portion of the pattern to another, for example from right to left, to simulate the movement of words such as an advertising slogan.
In recent times, illuminated signage has also found widespread usage on motorized vehicles, such as buses, commuter trains, billboards, and taxicabs, to name but  a few. Since advertising is a lucrative field, particularly in areas of high population densities such as large cities, several workers have provided patented advances in this art. A few patents relating to such advertising or other means for displaying messages are now mentioned as background information, and the entire contents of each of these are herein incorporated by reference thereon.
U.S. Pat. No. 4,067,128 teaches an indicator for a taxi cab, which comprises: a) a housing having at least one window through which can be displayed; b) a means to fix the housing to an exterior surface of the vehicle; c) a rotatable indicator having a plurality of positions to display alternate information relating to the condition of the taxi; d) a means to move the indicator through a limited arc, which includes a pair of solenoids interconnected by a rod forming the armature for the solenoids; e) a pair of spaced guides attached to and projecting from the rod to slidably engage therebetween a crank pin on a crank mounted on the indicator, wherein the solenoids move the rod longitudinally from a central position, whereby the rod movement causes partial rotation of the indicator to its the positions.
U.S. Pat. No. 4,860,476 provides message display apparatus for an automobile window comprising: a) a display member assembly comprised of a housing, wherein the housing has a display board, an array of holes, a reflective back, and passive pin lights in each hole of the array of holes; b) a transparent lens located in front of the display board; c) a peripheral recess formed around the front of the housing to accommodate the display member assembly and transparent lens; d) a means for mounting the housing and display  member assembly adjacent to an automobile window; and e) means for illuminating the display member assembly.
U.S. Pat. No. 5,132,666 sets forth a display and mounting deck combination, comprising: a) a rectilinear, adjustable mounting deck adapted to connect to a roof portion of a vehicle, including slidably adjustable side arms for adjusting a center mounting area of the mounting deck to fit different sizes of displays, wherein each of the adjustable side arms further include two slidable frames having hollow track sections slidable upon a middle bar; b) a tensioning means attached to the adjustable side arms to provide slidable adjusting tension to the adjustable side arms, wherein the tensioning means includes an adjustable tensioning spring; c) a variable information display supported by the mounting deck; and d) a fixed information display mounted to the variable information display.
U.S. Pat. No. 5,151,679 shows a sign comprising at least one light pipe of a suitable material of uniform index of refraction having a longitudinal axis of extension, which is made of light-transmitting material, and which has two ends and carries at least one light source that is a light-emitting diode that is disposed proximate at one end wherein the light source is contained in the end. The light source is directed towards the other end of the light pipe in the direction of the longitudinal axis of extension of the light pipe. A portion of the outer surface of the light pipe is translucent and permits light to exit therefrom. The sign further carries an electrical circuit means for energizing the light source, and a means for mounting the light pipe to display the predetermined message or design. Energizing the light source causes light to be transmitted in the light pipe, and  light therefrom emerging through the translucent outer surface of the light pipe yields a display of the predetermined message or design.
U.S. Pat. No. 5,438,780 details an information display apparatus, comprising: a) an elongated roller; b) a screen of soft material that can be wound up on the roller attached at one side of the screen to the roller; c) a bar attached to the screen on a second side of the screen opposite to the roller; d) at least one folding arm connected between the bar and a member which is fixed adjacent to and relative to the roller; e) a spring-biasing means for extending the at least one folding arm and, thereby, separating the bar from the roller such that the screen is unwound from the roller to a fully-extended position solely by the force of the spring-biasing means; f) a means for rotating the roller such that the screen is wound around the roller and the bar is moved towards the roller against the direction of the bias of the spring-biasing means; g) a means for attaching the apparatus to a roof rack of a vehicle. The screen is formed out of a net fabric having sufficiently-sized holes therethrough that there is a visibility through the screen and such that air can readily pass through the screen, even when the screen is attached to a vehicle and driven in road use. The apparatus includes at least one warning light mounted on the bar, and the bar is at a position substantially vertically above the roller.
U.S. Pat. No. 5,657,566 provides rapid mount advertising panels for motor vehicles that comprise a plurality of panels having a first and last panel. Each of the panels containing a top portion, a bottom portion, a center portion, a back side, a front, a central retaining plate and cavity located on the back side of each of the panels, wherein the central cavity has a top and a bottom. There is at least one bottom retaining plate and  bottom cavities located on the front and near the bottom portion of each of the panels. Each of the bottom cavities has a top and a bottom. There is an air foil means attached to the front and back side respectively of the first and last panels, and an upper bracket means for receiving and securing the top portion of each of the panels. There is a central bracket means for engaging and securing the center portion of each of the panels, and lower bracket means for receiving and securing the bottom portion of each of the panels. Also provided are latching and locking means for latching the bottom portion of each of the panels, and locking means for locking the bottom latching means.
U.S. Pat. No. 5,905,434 discloses a vehicle communications system having a remote control unit installed in the interior of a vehicle and a display unit located on the exterior of the vehicle. The display unit has an input from the remote control unit and an input from a vehicle interface module that has inputs from the vehicle such as the braking system and the turning signal system. The remote control unit is controllable by the driver in the vehicle and has a table of preset and preprogrammed messages selectable by the driver. The driver selects a message to be displayed and sends the message to the display unit. Any input to the vehicle interface module from the vehicle signaling systems overrides the signal input from the remote control unit unless the display unit is mounted on the front of the vehicle. The driver can select a message from a table of messages that are sequentially displayed on the remote control unit. The table of messages is stored on a flash memory in the remote unit and in a flash memory in the display unit. The table of messages in the remote unit is programmable via a USB programming port. The table of  messages in the display unit can be programmed via an RF signal sent to the display unit by the remote unit.
U.S. Pat. No. 6,060,993 sets forth a mobile system for conveying messages, which comprises a vehicle adapted to traverse a geographic region, wherein the region is segregated into zones. It includes a display carried by the vehicle, and a controller associated with the vehicle, wherein the controller is operably connected to the display. The controller drives the display to generate a publicly viewable message selected for a first zone within which the vehicle is located. There is a means operably connected to the controller for generating signals indicative of the geographic location of the vehicle, wherein the controller receives the signals indicative of the geographic location of the vehicle and determines when the vehicle has entered a different zone for which the message has not been selected for display, and driving the display to generate a different message selected for display in the different zone.
U.S. Pat. No. 6,118,418 shows a pixel for use in a visual matrix display comprising: a) a frame having front and rear surfaces, and defining an aperture; b) a light source oriented in the aperture; c) a first retroreflective surface borne by the frame and positioned adjacent to the aperture; d) a flap borne by the front surface and moveable along a given path of travel between a first position wherein the pixel is non-operational, and the flap is disposed in covering relation relative to the light source, and the first retroreflective surface, to a second operational position, and wherein the flap has a second retroreflective surface which is exposed when the flap is oriented in the second position; e) means borne by the frame for selectively moving the flap along the given path of  travel; and f) means for energizing the light source when the flap is in one of the given positions along the path of travel.
U.S. Pat. No. 6,195,016 details a fiber optic display system comprising: a) a plurality of fiber optics having first and second ends, wherein the first ends are arranged in a bundle to receive an image, and wherein the fiber optics couple an image to the second ends thereof for displaying the image wherein the spacing between the second ends of the fiber optics is greater than the spacing between the first ends in the bundle; b) an image generator that generates an image received by the first ends of the fiber optics; and c) an array of lenses for receiving light from the second ends of the fiber optics, wherein the lenses aim the light from the fiber optics to control the viewing angle of the image displayed.
U.S. Pat. No. 6,198,872 provides a programmable display device comprising: a) a panel having opposed front and rear faces and a plurality of apertures extending therethrough; b) a plurality of optical fibers, wherein each the optical fiber having an emitting end and a receiving end, the emitting ends of the optical fibers being mounted in the respective apertures such that the receiving ends of the optical fibers are spaced from the rear face of the panel; c) a plurality of LED's, each LED being connected in juxtaposed to the receiving at least one optical fiber; and d) a control circuit for generating a programmed sequence of signals for selectively illuminating the LED's, such that the LED's direct light into the receiving end of each the optical fiber connected thereto, and such that light from the respective light emitting diodes are directed through  the optical fibers and from the emitting ends of the optical fibers at the front face of the display panel.
U.S. Pat. No. 6,236,330 teaches a mobile system for conveying messages, which includes: a) a display; b) a transporter associated with the display for moving the display from one location to another; c) a controller associated with the display for driving the display to generate a visual message; d) a fixed station located remote from the display; e) an advertiser located remote from the display; f) a communications link between the advertiser and the station for transmitting visual message content and scheduling data from the advertiser to the station; and g) a communications link between the station and the controller for transmitting visual message content and scheduling data. The controller drives the display to generate the visual message content pursuant to the scheduling data.
U.S. Pat. No. 6,265,984 discloses a pre-programmed device for displaying images, comprising: a) a plurality of electrically powered light emitters in one or more generally continuous rows, wherein the display device is capable of being moved in a path generally perpendicular with the row of lights; b) at least one microprocessor, wherein the light emitters are under direct control of at least one microprocessor; c) at least one motion or speed sensor within the display device; d) a source of electrical power within, on, or connected to the display device; and e) at least one input/output microprocessor pin on the microprocessor, wherein at least one input/output microprocessor pin drives at least one multicolor light emitting diode; and at least one of the sensors enables the microprocessor. The microprocessor turns individual light emitters on and off in a time-controlled  manner, in order that graphics, words or messages are displayed when the display device is moved at or above a rate of speed sufficient to be seen by people.
U.S. Pat. No. 6,371,637 sets forth a flexible, low profile lighting system, comprising: a) a flexible printed circuit board substrate that is flexible through at least two axes of rotation, which substrate is adapted to support and electrically interconnect surface mount electronic components; b) a plurality of surface mount light emitting diodes, wherein the plurality of light emitting diodes are surface mounted on the flexible printed circuit board substrate, so as to define a conformably bendable lighting array configured for mounting upon surfaces with compound curvature substrate. The array outputs a uniform light intensity of at least 2000 millicandles per square centimeter.
Thus, it is seen that display means for displaying text and other messages which employ light emitting diodes (“LED's”) have come into popular usage, particularly with recent developments in diode technology which have permitted increased brightness of the LED's.
However, of all of the display means which have been provided by the prior art which are in popular usage, none are suitable for employment in front of, or behind a window through which a person must be able to see during the course of normal daily activity. This is because none of the prior art means for displaying messages are sufficiently translucent to enable a person to see through both the window and a sign disposed in front of the window, either while a message is displayed on the sign or when no message is being displayed. Rather, the display signs of the prior art are all disposed about a black or other opaque background. The use of black or other opaque backgrounds  inherently makes such display signs in general unsuitable for being disposed in such locations as the side or rear windows of automobiles or other motorized vehicles, whose drivers by necessity must be able to have uninhibited vision through such windows.
Thus, if a translucent sign means were provided, such would enable the back window of taxicabs to be used for advertising purposes. In addition, disposing a sign in the rear window of a motorized vehicle enables communication between the drivers of the vehicles. The present invention solves this problem, and provides an illuminated sign having an electronically-alterable message that may be disposed in such locations as the rear window of automobiles (or other places where vision through a window is required), thus rendering such locations accessible to advertising and other visual communications and visual effects. 